1. Field of the Invention
The present invention relates to liquid separation, more specifically to a grated inlet surface drain which includes clog resistant reinforcement for passing liquids contaminated with particulate and chemical waste that would normally cling to and block a drain grate of common design. The present drain grate is designed to support unusually large loads while providing the above characteristics, and be easily removable from a drain frame with simple hand tools.
2. Description of the Prior Art
The typical drain grate is designed to support traffic loads ranging from pedestrian traffic to heavy wheeled vehicles. It is usually made from cast iron or steel, for strength, although one of a small surface area may be made from plastic, and rests in a recessed frame in the ground. It is held in place by friction, but is occasionally screwed down to the frame.
The frame comprises the top portion of a drain box which is set into the ground. The drain box is connected to a sewer pipe.
The grate comprises a wall that is thick enough to bear the weight of traffic. The wall includes openings for passing liquids therethrough from the top into the drain box.
One floor drain grate is described in U.S. Pat. No. 4,910,811 patented Mar. 27, 1990 by L. B. Izzi, Sr. The assembly is designed for use in a factory floor where corrosive liquids are likely to enter a drain and damage a metal drain assembly.
The assembly includes a bowl-shaped connector body, and a strainer plate, each of which is molded from a rigid plastic material.
The strainer plate comprises a load bearing wall of uniform thickness, defining a plurality of round holes through the wall in a direction normal to the plane of the wall. The plate has a lower surface that is received on an annular seat within the rim of the connector body.
A plurality of positioning pins extend normally from the lower surface of the plate. The positioning pins are received in interference fit within in a series of circumferentially spaced positioning apertures in the top of the seat.
The plate fits within a recess in the rim so that the top of the plate is substantially flat with the surface of the floor when the connector body is installed in the floor.
U.S. Pat. No. 4,345,998 patented Aug. 24, 1982 by Graffis et al. discloses a plastic drain grate for a plastic catch basin in which the drain grate comprises a load bearing wall of uniform thickness having an inverted channel around the periphery for rigidity and for nesting snugly and optionally with a friction fit within the frame of the catch basin. The wall comprises a rectangular grid of square apertures directed through the wall normally to the plane of the wall.
A system for collecting liquid spillage at rail facilities, described in U.S. Pat. No. 4,300,721, patented by B. Rich on Nov. 17, 1981, includes collector pans which rest across the railroad ties. Each pan connects into a drain pipe which runs between the ties.
The pan comprises a plate of uniform thickness that is formed with a shallow depression for draining liquids toward a hole through the plate. The top of the plate includes a molded non-skid thread.
The bottom of the plate included intersecting longitudinal and transverse reinforcing ribs which terminate short of the edge margins of the plate where they taper down to meet the plate.
The inner wall of the hole extends below the plate via a nipple which is integrally molded within one of the ribs.